Four fine milks, in four glasses.

They were poured and shuffled while I was in another room. I tasted them without knowing which is which, all though these were all milk I had tried before.

Rosa Brothers

Rosa Brothers was the most distinctive, having a visibly whiter color and the clearest taste by a wide margin.

Maple Hill

The Maple Hill is also distinctive, being very smooth and homogenous with a well balanced creaminess.

Alexander

Unfortunently this particular bottle of Alexander was not very fresh (I suspect the supplychain failed to keep it cold), so it had a noticably worse taste. Alexander seems to be the only brand prone to this quality inconsistency.

Straus

Straus is a little similar to Maple Hill or Alexander (a good one), but generally will have more lumps of cream floating around.

Conclusion

I correctly identified all four milks.

St Benoit and Rosa are the best of this group (e.g. around A/A+), with Straus a little behind (A-). The bad Alexander was far behind the others (C+? a good Alexander can land around A/A-).